A young woman with short blond hair, wearing jeans and a Nike top, is walking around a studio, singing. She stops by a painting on an easel. The lyrics of her song appear to be describing what's in the picture:

Here is a painting, who dares look?

A broken lock, a turned-over flat,

A favourite dog, with his head sliced off

The song has something about Dido to it, though this singer doesn't have Dido's voice. She obviously isn't trained, but sings clearly, and in tune. She comes to another painting:

Mother framed in a door with a bag

To take the rubbish out and never come back

It becomes obvious she's singing about her personal experience. And these are her paintings. That's a back view of her own mother framed in a door, with a bag. She went out with the rubbish and never came back, leaving daughter Sam, then still a child, with an abusive, alcoholic father.

We're in the art room of Downview Prison. It's during the chorus of the song that we learn why Sam is inside.

So ask me again what I'm doing here,

My brother's bleeding, my husband's on fire

And that's not a metaphor or anything, it's what happened. Sam stabbed her brother, and then set light to the house her husband was in. She got five years for arson.

This is Songbirds (Channel 4), and there's something very wonderful about it. It's a collaboration between poet Simon Armitage, composer Simon Boswell, director Brian Hill, plus the women of Downview and their stories. The result may not have the gloss and the glamour of MTV but it makes up for it in grit.

Mary raps about robbing and tamazepam, of prison being a second home, about being "scary". Charmaine sings about being abused in Jamaica. Claire, who has a lot of Mike Skinner about her, does a very Streets-like song about how it all started when she robbed an Arsenal top for her brother. It's all very real and raw and all that, but there's room for humour in there as well.

The drug smugglers, nearly all of whom are foreign, probably have the least to laugh about, given the length of their sentences (two girls caught smuggling ecstasy for example got 18 years each). But their song, Muling It, a cheesy number with a Caribbean flavour to it, is a hoot:

You can mule it in a car

You can mule it in your bra

You can mule it in your booze

You can mule it in your shoes

You can mule it in your gut

You can mule it in your butt

You can mule it in a sack

You can mule in the back

You can mule it in the front

You can mule it . . . in . . . your . . .

Mule it, mule it, mule it, mule it

There's a whole room of these smuggling ladies, all singing along, while doing their menial work - assembling headphones. It's like a scene from the Blues Brothers. One of the screws even gets a part, as the voice of the law:

There's something in your luggage

Unless I'm very much mistaken

Her Majesty's prison

Is your final destination

I wonder what sort of bureaucratic nightmare it was to get this whole thing off the ground. Perhaps it was made easier by the success of the team's first project, the equally wonderful Feltham Sings. But I'm sure it wasn't just a case of turning up at the gates of Downview and being let in to make music and film. I suspect there was a lot of persuasion and red tape to get through first. And Downview must have a very enlightened governor.

Anyway I'm glad they persevered because the resulting film is terrific - powerful, moving, bleak, funny and hopeful, all at the same time. I won't be rushing out to buy the accompanying CD if they bring one out. But a polished soundtrack would have been too much to ask for - Hollywood can do that version.